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Vitamin D status and weight loss: a systematic review and meta-analysis of randomized and nonrandomized controlled weight-loss trials.
Am J Clin Nutr. 2016 10; 104(4):1151-1159.AJ

Abstract

BACKGROUND

Obesity is associated with lower concentrations of serum 25-hydroxyvitamin D; however, uncertainty exists as to the direction of causation. To date, meta-analyses of randomized controlled vitamin D-supplementation trials have shown no effect of raising circulating vitamin D on body weight, although several weight-loss-intervention trials have reported an increase in circulating vitamin D after weight reduction.

OBJECTIVE

We undertook a systematic review and meta-analysis of randomized and nonrandomized controlled trials to determine whether weight loss compared with weight maintenance leads to an increase in serum 25-hydroxyvitamin D.

DESIGN

A systematic search for controlled weight-loss-intervention studies published up to 31 March 2016 was performed. Studies that included participants of any age with changes in adiposity and serum 25-hydroxyvitamin D as primary or secondary outcomes were considered eligible.

RESULTS

We identified 4 randomized controlled trials (n = 2554) and 11 nonrandomized controlled trials (n = 917) for inclusion in the meta-analysis. Random assignment to weight loss compared with weight maintenance resulted in a greater increase in serum 25-hydroxyvitamin D with a mean difference of 3.11 nmol/L (95% CI: 1.38, 4.84 nmol/L) between groups, whereas a mean difference of 4.85 nmol/L (95% CI: 2.59, 7.12 nmol/L) was observed in nonrandomized trials. No evidence for a dose-response effect of weight loss on the change in serum 25-hydroxyvitamin D was shown overall.

CONCLUSIONS

Our results indicate that vitamin D status may be marginally improved with weight loss in comparison with weight maintenance under similar conditions of supplemental vitamin D intake. Although additional studies in unsupplemented individuals are needed to confirm these findings, our results support the view that the association between obesity and lower serum 25-hydroxyvitamin D may be due to reversed causation with increased adiposity leading to suboptimal concentrations of circulating vitamin D. This trial was registered at www.crd.york.ac.uk/PROSPERO/ as CRD42015023836.

Authors+Show Affiliations

Department of Human Nutrition, University of Otago, Dunedin, New Zealand simonette.mallard@otago.ac.nz.Department of Human Nutrition, University of Otago, Dunedin, New Zealand.Department of Human Nutrition, University of Otago, Dunedin, New Zealand.

Pub Type(s)

Comparative Study
Journal Article
Meta-Analysis
Review
Systematic Review

Language

eng

PubMed ID

27604772

Citation

Mallard, Simonette R., et al. "Vitamin D Status and Weight Loss: a Systematic Review and Meta-analysis of Randomized and Nonrandomized Controlled Weight-loss Trials." The American Journal of Clinical Nutrition, vol. 104, no. 4, 2016, pp. 1151-1159.
Mallard SR, Howe AS, Houghton LA. Vitamin D status and weight loss: a systematic review and meta-analysis of randomized and nonrandomized controlled weight-loss trials. Am J Clin Nutr. 2016;104(4):1151-1159.
Mallard, S. R., Howe, A. S., & Houghton, L. A. (2016). Vitamin D status and weight loss: a systematic review and meta-analysis of randomized and nonrandomized controlled weight-loss trials. The American Journal of Clinical Nutrition, 104(4), 1151-1159.
Mallard SR, Howe AS, Houghton LA. Vitamin D Status and Weight Loss: a Systematic Review and Meta-analysis of Randomized and Nonrandomized Controlled Weight-loss Trials. Am J Clin Nutr. 2016;104(4):1151-1159. PubMed PMID: 27604772.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Vitamin D status and weight loss: a systematic review and meta-analysis of randomized and nonrandomized controlled weight-loss trials. AU - Mallard,Simonette R, AU - Howe,Anna S, AU - Houghton,Lisa A, Y1 - 2016/09/07/ PY - 2016/04/18/received PY - 2016/08/02/accepted PY - 2016/9/9/pubmed PY - 2017/6/10/medline PY - 2016/9/9/entrez KW - meta-analysis KW - obesity KW - serum 25-hydroxyvitamin D KW - vitamin D KW - weight loss SP - 1151 EP - 1159 JF - The American journal of clinical nutrition JO - Am. J. Clin. Nutr. VL - 104 IS - 4 N2 - BACKGROUND: Obesity is associated with lower concentrations of serum 25-hydroxyvitamin D; however, uncertainty exists as to the direction of causation. To date, meta-analyses of randomized controlled vitamin D-supplementation trials have shown no effect of raising circulating vitamin D on body weight, although several weight-loss-intervention trials have reported an increase in circulating vitamin D after weight reduction. OBJECTIVE: We undertook a systematic review and meta-analysis of randomized and nonrandomized controlled trials to determine whether weight loss compared with weight maintenance leads to an increase in serum 25-hydroxyvitamin D. DESIGN: A systematic search for controlled weight-loss-intervention studies published up to 31 March 2016 was performed. Studies that included participants of any age with changes in adiposity and serum 25-hydroxyvitamin D as primary or secondary outcomes were considered eligible. RESULTS: We identified 4 randomized controlled trials (n = 2554) and 11 nonrandomized controlled trials (n = 917) for inclusion in the meta-analysis. Random assignment to weight loss compared with weight maintenance resulted in a greater increase in serum 25-hydroxyvitamin D with a mean difference of 3.11 nmol/L (95% CI: 1.38, 4.84 nmol/L) between groups, whereas a mean difference of 4.85 nmol/L (95% CI: 2.59, 7.12 nmol/L) was observed in nonrandomized trials. No evidence for a dose-response effect of weight loss on the change in serum 25-hydroxyvitamin D was shown overall. CONCLUSIONS: Our results indicate that vitamin D status may be marginally improved with weight loss in comparison with weight maintenance under similar conditions of supplemental vitamin D intake. Although additional studies in unsupplemented individuals are needed to confirm these findings, our results support the view that the association between obesity and lower serum 25-hydroxyvitamin D may be due to reversed causation with increased adiposity leading to suboptimal concentrations of circulating vitamin D. This trial was registered at www.crd.york.ac.uk/PROSPERO/ as CRD42015023836. SN - 1938-3207 UR - https://www.unboundmedicine.com/medline/citation/27604772/Vitamin_D_status_and_weight_loss:_a_systematic_review_and_meta_analysis_of_randomized_and_nonrandomized_controlled_weight_loss_trials_ L2 - https://academic.oup.com/ajcn/article-lookup/doi/10.3945/ajcn.116.136879 DB - PRIME DP - Unbound Medicine ER -